1. Field of the Invention
The present invention relates to a cooling device and an electronic apparatus using the same.
2. Description of Related Art
Recently, a semiconductor device installed in an electronic apparatus such as a computer, that is, a central processing unit (CPU) has its heat release amount increased resulting from higher integration, higher processing speed, and sophisticated structure. Meanwhile, when a temperature of the semiconductor device exceeds a predetermined value, it may fail to maintain its performance, and in the worst case, it may be broken. The semiconductor device which releases higher heat value is required to be subjected to a temperature control through cooling.
A rack mount type electronic apparatus such as a server has been increasingly employed as it allows a system to be flexibly structured to suit user's needs, and the system to be further extended in response to a change in the user's needs. The rack mount type allows individual devices each with different function and performance to be detachably selected and arranged to form the electric apparatus, resulting in a compact system structure.
With the aforementioned background, an electronic circuit substrate (CPU blade) provided with the semiconductor device (CPU) having the heat value increased is mountable on the electronic apparatus (blade server) while exhibiting a cooling function by means of a cooling device having high performance.
With the rack mount type, a liquid cooling system in the blade server is detachable by an auto-shutoff valve for directly cooling heat generated by the semiconductor device in the CPU blade installed in a detachable information processor by a cooling medium via a heat receiving jacket attached to the semiconductor device as disclosed in Document 1 (Japanese Patent Laid-open No. 2002-374086).
Document 2 (Japanese Patent Laid-open No. 2007-72635) discloses a technology which copes with a space occupied by the liquid-cooled system in the electronic apparatus, and provision of an exclusive casing.
Document 3 (Japanese Patent Laid-open No. Hei 07-122869) discloses a socket type thermal connector for thermally connecting an external cooling system with the semiconductor device of the CPU blade for simplifying detachment of the CPU blade.
Document 4 (Japanese Patent Laid-open No. Hei 06-4179) discloses a technology for thermally connecting the external cooling system.
Document 5 (Japanese Patent Laid-open No. 2007-89397) discloses a power converter which is connected to a heat generating portion of the electronic circuit, provided with a stack including a heat pipe for cooling the heat generating portion, and has a stack detachably supported.
With the method for cooling the rack mounted information processor disclosed in Document 1, the cooling medium is supplied from the liquid-cooled system built in a cabinet to a passage in a pillar which constitutes the cabinet, and the passage pipe with a liquid-cooled structure inside the detachable rack is connected via the auto-shutoff valve so as to form the liquid-cooled system. The method allows a direct use of the rack with an air-cooled fan.
A configuration of the liquid-cooled system is limited as it is mounted on the cabinet rack, thus failing to cope with substantial improvement in the system performance. There may be some concern of liquid leakage caused by connection error with the auto-shutoff valve. Description with respect to the increase/decrease in the heat generated by the semiconductor device on the CPU blade, and consideration for a fluctuation is not disclosed in the document.
In the liquid-cooled system disclosed in Document 2, a heat receiving jacket connected to a pipe drawn to outside the electronic apparatus is attached to the semiconductor device of the CPU blade mounted on the electronic apparatus, and the liquid-cooled system is disposed on a door at a back surface of the electronic apparatus to cool a radiator of the liquid-cooled system with a fan inside the electronic apparatus. The liquid-cooled system is intensively arranged on a door at a back surface of the rack, the cooling system may be changed without changing a rack portion.
As the fan in the electronic apparatus is used for cooling the radiator of the liquid-cooled system, the cooling performance is only derived from the fan which is not connected to the liquid-cooled system. As the heat receiving jacket is detachably connected to the liquid-cooled system with a joint, there may be some concern of liquid leakage caused by the connection error likewise Document 1.
The cooling mechanism of the electronic apparatus disclosed in Document 3 is detachably installed together with the CPU blade in the cooling system with the heat pipe attached to the semiconductor device of the CPU blade. The heat pipe is thermally connected to the cooling system with the socket structure having the cooling mechanism attached to the electronic component. This allows the CPU blade to be easily detached and exchanged upon such work as repair and maintenance.
As the cooling system and the electronic apparatus are individually formed in the casings, and integrally connected, the exchange of the cooling system in accordance with the heat generation value of the semiconductor device on the CPU blade is not considered.
In the structure for cooling the semiconductor device on the CPU blade disclosed in Document 4, the CPU blade is combined with the cooling system into a unit so as to be detachably connected to a refrigerant of the external cooling system via the joint. The thus heated refrigerant at the high temperature in the refrigerant cooling device may be heat exchanged with the cooling liquid or the cooling air. However, specific description with respect to a structure of the heat exchanger is not provided, thus failing to provide sufficient cooling performance. As the refrigerant cooling device inside the CPU blade is detachably connected to the external cooling system with the joint, there may be some concern of liquid leakage caused by the connection error likewise the Document 1.
The aforementioned related art has problems to be solved for the purpose of optimally cooling with respect to the heat generated by the semiconductor device of the CPU blade to be attached and detached.
It is an object of the present invention to provide a cooling device for optimally cooling the semiconductor device on the CPU blade which is detachable with respect to the electronic apparatus, and an electronic apparatus using the cooling device with compact structure for reducing power consumption.